[Two cases of primary low spinal fluid pressure syndrome with pachymeningeal gadolinium enhancement].

We report two patients with primary low spinal fluid pressure syndrome with pachymeningeal gadolinium enhancement. Case 1 was a 36-year-old man and case 2 was a 29-year-old man. Each case developed postural headache and had no histories of head trauma, craniotomy or lumbar puncture. The spinal fluid pressures were 20 mmH2O in case 1 and 0 mmH2O in case 2 at decubitus position. Cranial MRIs revealed diffuse pachymeningeal enhancement after gadolinium infusion, flattening of the pons, and tight posterior fossa in each case. Their headache spontaneously resolved within a couple of weeks by bed rest and intravenous hydration. Follow-up MRIs which were examined 3 or 4 months later, revealed a remarkable reduction in the degree of pachymeningeal enhancement, flattening of the pons and tight posterior fossa. Primary low spinal fluid pressure syndrome should be included in the differential diagnosis of pachymeningeal enhancement on MRI.